Wet charged percussion cap



April 22, 1969 GAWLJCK ET AL WET CHARGED PERCUSSION CAP Filed Sept. 21,1967 FIG. 2b

FIG. lb

' INVENTORS HEINZ GAWLICK FlG.3b

mum BENDLER BY p 9 ATTORNEY- United States Patent 3,439,618 WET CHARGEDPERCUSSION CAP Heinz Gawlick and Hellmut Bendler, Furth, Germany, as-

signors to Dynamit Nobel Aktiengesellschaft, Troisdorf, Germany FiledSept. 21, 1967, Ser. No. 669,628

Int. Cl. F42c 19/10 US. Cl. 102-865 Claims ABSTRACT OF THE DISCLOSUREThe present disclosure relates to a primer cap, particularly of thefiring pin percussion type, wherein the primer charge is introduced intothe capsule of the primer cap by moist charging with an anvil providedon the primer charge and fastened to the capsule. The drying of the wetprimer charge is facilitated by providing the anvil with a projectionthat molds the primer charge into a cup shape between the anvil andcapsule during insertion. The anvil may be provided with a plurality ofradially extending webs for engaging the sides of the capsule andproviding spaces therebetween for receiving the primer charge so that itmay be exposed to the outside for drying. Also, the anvil may be made ofa permeable porous synthetic material or an impermeable syntheticmaterial provided with perforations, to provide for the quick drying ofthe wet primer charge.

The dry charging of primer caps, particularly firing pin percussioncaps, is particularly dangerous. Therefore, it has been advantageous, inregard to safety, to charge the primer caps with a wet primer charge;this has become increasingly popular. With wet charging, the primercomposition or charge is introduced into the percussion cap capsule inthe moistened condition and subsequently dried during storage within thecapsule.

With dry charging of primer caps, the required amount of primercomposition is easily pressed into the percussion cap in a uniform andrelatively thick layer, for example 3-4 millimeters in thickness. Withthe prior art, it has been impossible to wet charge the primercomposition in such a manner, that is in a uniform and relatively thicklayer, because a uniform and thick layer of wet primer composition couldnot be dried satisfactorily.

It is an object of the present invention to provide for the wet chargingof the primer composition with resulting safety advantages whileovercoming the above-mentioned disadvantages of the prior art in regardto drying. Therefore, the present invention provides a primer cap,particularly a firing pin percussion cap with a primer compositionintroduced in the percussion cap in a moistened condition and with ananvil provided on the primer composition and fastened to the primercapsule to impart to the primer composition a bowl-shaped or cup-shapeddistribution during charging by means of a projection on the anvil. Withthis feature, the surface area of the primer composition is greatlyenlarged as compared to the surface area of a similar amount of primercomposition in a conventional ararngement, and at the same time thethickness is reduced to such an extent that the uniform and completedrying of the primer charge is assured.

The anvil is preferably constructed of a synthetic material, for examplea synthetic polymer such as polyvinyl chloride or polyethylene. Theprimer cap capsule is preferably made of these same materials. The anvilmay be knotted within the capsule by means of a plurality of radiallyextending webs or arms distributed along the circumference of the anvilin a star-shaped manner to securely clamp the anvil by means of a pressfit with the inner walls of the capsule.

In order to further the drying process of the wet primer 3,439,618Patented Apr. 22, 1969 composition, or to accelerate the same, it isfurther proposed to make the anvil of a permeable porous syntheticmaterial, or of a synthetic material that is impermeable and providedwith perforations.

Further objects, features and advantages of the present invention willbecome more clear from the following detailed description of severalpreferred embodiments of the present invention with reference to theaccompanying drawing, wherein:

FIGURES la and 1b show respectively a plan view and an axial crosssectional view of a primer cap according to the present inventiontogether with the firing pin (FIG- URE lb being taken on the indicatedcross section line of FIGURE la);

FIGURES 2a and 2b are views similar to FIGURES la and lb, respectively,but of a further specific embodiment of a primer cap according to thepresent invention; and

FIGURES 3a and 3b are views similar to FIGURES la and 1b, respectively,but show an additional specific embodiment of a primer cap according tothe present invention.

As shown in FIGURES la and lb, the cup-shaped capsule 1 is provided witha discshaped (preferably cylindrical) bottom 2 that has a relativelythin central zone, and a tubular relatively thick outer wall 3, which ispreferably also cylindrical. Preferably, the capsule 1 is constructed ofa soft thermoplastic synthetic polymer material. The recess 4 is filledwith a charge 5 that has been pressed by and is held in position by themandrel-type anvil 6 provided with the perforations 7. The percussion orfiring pin 8 is indicated in FIGURE 1b above the percussion capimmediately opposite the central relatively thin zone of the bottom 2.The primer charge is in a generally bowl-shaped or cup-shapedconfiguration of a relatively large surface area for rapid drying and isfurther subjected to the drying medium by means of the perforations 7.

In place of the perforated or hollow-cylindrical anvil of FIGURJES 1aand 1b, the anvil 6 of FIGURES 2a and 2b is provided in the shape of astar with four webs or arms 10 uniformly distributed about thecircumference thereof at equal distances. The arms 10 tightly engage theinterior cylindrical surface of the capsule 1, that is otherwiseidentical to the capsule 1 of FIGURES 1a and 1b, to provide a force fitfor rigidly securing the anvil 6 within the capsule 1. The anvil 6 isprovided with a central spike-shaped projection 9 extending toward theprimer charge and bottom of the capsule; the projection 9 is pressedinto the primer composition to form the primer composition into abowl-shape or cup-shape. As in 'FIGUR'ES 1a and 1b, the central zone ofthe bottom of capsule 1 is relatively thin, when compared to the outerside Walls of the capsule 1; this feature has the advantage of providingonly negligible resistance to the firing pin so that ignition of theprimer charge is not delayed (the firing pin not being shown in FIGURES2a and 2b). The drying of the primer composition, that is introduced inthe moist state, may be accomplished with the embodiment of FIGURES 2aand 2b by way of the zones located between the adjacent webs 10, whereinthe primer charge is exposed to the outside.

It is contemplated that the features of FIGURES 1a and 1b and FIGURES 2aand 2b may be combined in a single primer cap wherein the centralportion of the anvil 6 or projection 9 of FIGURES 2a and 2b may beprovided with perforations similar to perforations 7 shown in FIGURES 1aand lb.

Although the capsule 1 shown in FIGURES 3a and 3b differs from thecapsule 1 in FIGURES 1a, lb, 2a and 2b only in its externalconfiguration, it is contemplated that the external configuration may bethe same. As shown in FIGURES 3a and 3b, the anvil 6 is provided withradially extending arms or webs 10 arranged in a star-shaped mannerabout the central projection 9 that presses into the primer compositionto mold it into a cup shape. In contrast to FIGURES 2a and 2b, the armsof FIGURES 3a and 3b extend axially to the bottom, as viewed in FIGURE3b, and radially outward over the front face of the capsule 1 of theprimer cap and terminate flush with the outer cylindrical side walls ofthe capsule l. The anvil 6 is frictionally held in the capsule 1 by theinner portions of the arms 10 radially outward of the projection 9 andengaging the inner cylindrical surface of the capsule 1 and the outerportions of the arms 10 engaging the front face of the capsule 1.

It is contemplated that the features of FIGURES 3a and 3b may becombined with the above-noted combination of the features shown inFIGURES la, lb, 2a and 2b by providing the anvil 6 as shown in FIGURE 2bwith an identical front extension and radial extensions of the arms 10past the front face of the capsule 1 to terminate flush with the outercylindrical walls of the capsule 1, as shown in FIGURE 3b. Furthermore,it is contemplated that the anvil material as well as the capsulematerial may be either impermeable or porous to facilitate drying of thewet primer composition.

We claim:

1. A primer cap, particularly of the firing pin percussion type, with acapsule and a primer charge introduced into the capsule of the primercap by moist charging with an anvil provided on the primer charge andfastened in the capsule of the primer cap, in combination with theimprovement wherein the capsule is cup-shaped with a substantiallyclosed bottom end and a generally axially tubular side wall forming aforward open end, the primer charge is substantially cup-shaped toprovide a large surface area of relatively thin dimensions for quickdrying, the anvil has projection means extending toward the closed endof the capsule directly engaging and for molding the primer charge intothe cup-shape during insertion, the anvil includes a plurality ofintegral radially extending webs tightly engaging the interior surfaceof the capsule side wall with a press fit to securely hold said anvilwithin the capsule, said primer charge extends between said webs, andmeans exposing substantially the entire forwardly facing surface of saidprimer charge between said webs to the atmosphere.

2. The primer cap according to claim 1, wherein said anvil isconstructed of a relatively permeable porous syn- .hetic material toconstitute means for conducting air :hrough said anvil to the surface ofsaid primer charge :ngaging said anvil.

"3. The primer cap according to claim 1, wherein said anvil isconstructed of a relatively permeable porous naterial to constitutemeans for conducting air through aaid anvil to the surfaces of saidprimer charge engaging said anvil.

4. The primer cap according to claim 1, wherein said :apsule tubularside wall is cylindrical, said closed end is 1 bottom disk having acentral relatively weakened portion :hinner than the remainder of saiddisk to offer negligible 'esistance to a firing pin penetration, saidanvil is sub- :tantially cup-shaped opening in the same direction astaid cup-shaped capsule and being provided with a plu- 'ality ofperforations axially extending therethrough and arranged uniformly in acircle, said anvil and capsule being constructed of a synthetic polymermaterial, said primer charge extending forwardly into said perforation.

5. The primer cap according to claim 1, wherein said capsule tubularside wall is cylindrical, said closed end is a disk having a centralrelatively weakened section thinner than the remainder of said disk forproviding negligible resistance to penetration of a firing pin, saidanvil includes a central projection extending generally axially towardsaid weakened section, said primer charge extending forwardly into thespace immediately radially between a-djacent webs, said capsule and saidanvil being constructed of a synthetic polymer material.

6. The primer cap according to claim 5, wherein said anvil extendsaxially forwardly beyond the forwardmost surface of said capsule, andsaid webs have forwardmost portions radially extending outwardly andterminating flush with the adjacent outer axially extending surface ofsaid capsule tubular side wall, said primer composition generallyfilling the space between said webs and said capsule side wall.

7. The primer cap according to claim 6, wherein said anvil isadditionally provided with a plurality of axially extendingperforations.

8. A method of constructing a primer cap, comprising the steps of:introducing a wet primer charge into a cupshaped capsule; engaging ananvil directly with the wet primer charge, thereafter, forcing the anvilinto the wet primer charge toward the bottom of the capsule to mold thewet primer charge into a cup-shaped between the anvil and the capsule;conducting air through the anvil to the interior surface of thecup-shaped primer charge and simultaneously drying the primer charge.

9. The method according to claim 8, wherein said step of forcing theanvil into the wet primer charge includes molding the wet primer chargeforwardly toward the open end of the capsule between radially extendingwebs of the anvil.

10. The method according to claim 9, including the step of force fittingthe radially extending webs of the anvil into the capsule simultaneouslywith the step of forcing the anvil into the wet primer charge.

References Cited UNITED STATES PATENTS 256,684 4/ 188.2 Hobbs l0286.5

750,624 1/1904 Edmunds 102-865 3,119,338 1/1964 Pissacroia 10286.5 X3,121,394 2/1964 Anzalone 10.2-86.5 3,195,463 7/1965 Foote et al.10286.S

FOREIGN PATENTS 1,082,044 12/ 1954 France.

735,888 4/ 1943 Germany.

BENJAMIN A. BORCHELT, Primary Examiner.

GERALD H. GLANZMAN, Assistant Examiner.

US. Cl. X.R. 86-1

